Li-ion batteries should never be left charging unattended under any circumstances. The user must have knowledge of how to charge and discharge Li-ion batteries before using them. Always use a charger that is designed to recharge the particular Li-ion cell that you wish to recharge. Never use a DC adapter to charge Li-ion batteries. We are NOT responsible for any damage that is caused by the misuse of Li-ion batteries. We recommend charging any Li-ion cell on a metal or other non-flammable surface.